Anti-gravity

[hflathead]

When testing certain shield protectors on rockets that are to deploy in a weightless environment, a counter-balance, motor driven test rig is used to ‘simulate’ 0 G. This allows the shields to be moved with an ever-so-slight touch that simulates how they will work in space. Not quite an ‘anti-gravity machine’ but you need to simulate it none the less. later, Tom

[astro]

Waaaaaayyyyyy out my league… here but for all you particle mavens swimming in the deep end of the quantum pool why are gravitons so difficult/impossible to detect.

If they are some form of quanta surely there must be some way to detect them. What is the problem? Masslessness?
Why haven’t the folks studying this whose IQ is higher than their body weight been able to parse this out?

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The subatomic world, where particles are not solid objects
so much as smears of probability, may seem ounterintuitive, even illogical.

Tarlé concludes. “Primordial antimatter is not going to be seen,” he predicts. “It’s like looking for monkeys on the moon.”

[Drew_Blade]

When I was much younger I remember there being some question as to whether “gravitational mass” and “inertial mass” were the same thing. Has this question been answered, or is an answer not even considered necessary these days? Consider a subatomic particle moving very close to the speed of light. It has an inertial mass much greater than that of the same particle at rest. But does it have an equivalently greater gravitational field? Can a particle moving fast enough gain enough mass to become a black hole?

[Phobos]

**
why are gravitons so difficult/impossible to detect.
**

(1) they may not exist at all
(2) they would be unimaginably small (an atom would be larger than our solar system in comparison, IIRC)
(3) they would exist everywhere (THE fundamental particle?)

[JoeyBlades]

Sofis wrote:

The air which is affected by gravity would try to take its place and push it upwards.

Good point. I didn’t think about displacement.
Chronos wrote:

I have no clue how one might actually create a “null-gravity” device of some sort, but it’s quite likely that if it were possible, such a device would also eliminate all effects of inertia.

Why would you think that? Inertia and gravity are independent forces. Of course, we don’t know exactly what the principle of this device is, but unless it operates by reducing mass to zero, I would think that you could have inertia in a zero gravity environment.
MetallicAsh:

If gravity is just the curvature of spacetime in the presence of matter/energy (General Relativity), then it would seem to be unlikely that anything with positive mass could be immune…

Actually, nullifying mass wouldn’t be enough. Even a photon is affected by the curvature of space. The solution is that you simply have to find another way to distort space-time in the opposite manner in a small region of space. If you think about the rubber sheet analogy, it’s like the Earth is stretching the sheet away from the null plane and just in the vacinity of our device there’s an inverted spike that brings the sheet back up to the null plane.

etgaw1:

The Earth is spinning really fast we need some force to suppy the centriptal force to hold us to the earth. Gravity supplys this force. If you made a device that was sheilded from all gravity it would fly off in a path tangential to the rotation of the rotating earth. It is like if you whirl a ball on a string around your head and suddenly let go.

Well, it wouldn’t be tangental since, as has been pointed out, displacement by air that is now heavier than our device will generate a (mostly) perpendicular component to the vector. However, you’re right, I believe, the rotational inertia will prevent the resultant vector from being perpendicular to the gravitational force, as well.